biff

biff /bif/ /vt./ To notify someone of incoming mail. From
the BSD utility `biff(1)', which was in turn named after a
friendly golden Labrador who used to chase frisbees in the halls at
UCB while 4.2BSD was in development. There was a legend that it
had a habit of barking whenever the mailman came, but the author of
`biff' says this is not true. No relation to B1FF.